Method of making internal shapes in metal objects having smooth or toothed rotational outer surfaces

ABSTRACT

A method of shaping a plastically deformable sleeve by rolling jaws, having an internal shaping surface, on the sleeve after a shaping core has been placed in the bore of the sleeve. As a result of the rolling operation, the outer diameter of the material is reduced and the inner surface of the sleeve assumes the external shape of the core. The method enables simultaneous shaping of the outer and inner surface of the sleeve such as an outer toothing and a splined bore. In a particular embodiment in which internal threads are to be formed on the sleeve, an unrevolving core is used which is elastically biassed against axial displacement so that when the sleeve is rotated by the jaws in the course of shaping the core will be axially displaced against the elastic biassing action and the core will automatically advance over an axial feed distance when the jaws release the sleeve.

United States Patent Marciniak et a1.

[ 5] Feb. 18, 1975 METHOD OF MAKING INTERNAL SHAPES IN METAL OBJECTS HAVING SMOOTH OR TOOTHED ROTATIONAL OUTER SURFACES [75] Inventors: Zdzislaw Marciniak; Zeonon Kopacz, both of Warsaw, Poland [73] Assignee: Polichtechnika Warszawska,

Warsaw, Poland [22] Filed: Nov. 27, 1972 [211 Appl. No: 309,911

[30] Foreign Application Priority Data May 23. l972 Poland 155534 [52] US. Cl 72/76, 72/77, 72/189 [51] Int. Cl. B2lb [58] Field of Search 72/76. 77, 189

[56] References Cited UNITED STATES PATENTS 767,314 8/1904 Sandner 72/77 1,123,179 12/1914 Davis 72/77 1,450,947 4/1923 Gill 72/77 Fielding 72/189 Marciniak 72/76 [57] ABSTRACT A method of shaping a plastically deformable sleeve by rolling jaws, having an internal shaping surface, on the sleeve after a shaping core has been placed in the bore of the sleeve. As a result of the rolling operation, the outer diameter of the material is reduced and the inner surface of the sleeve assumes the external shape of the core, The method enables simultaneous shaping of the outer and inner surface of the sleeve such as an outer toothing and a splined bore. in a particular embodiment in which internal threads are to be formed on the sleeve, an unrevolving core is used which is elastically biassed against axial displacement so that when the sleeve is rotated by the jaws in the course of shaping the core will be axially displaced against the elastic biassing action and the core will automatically advance over an axial feed distance when the jaws release the sleeve.

4 Claims, 14 Drawing Figures PATENTED l 5 SHEET-'1 0F 3 HTEPHEU FEB 1 8 NH 3, 866.450

sum 2 or 5.

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METHOD OF MAKING INTERNAL SHAPES IN METAL OBJECTS HAVING SMOOTH OR TOOTHED ROTATIONAL OUTER SURFACES FIELD OF THE INVENTION a. Background The invention relates to a method of making internal shapes of theoretically unlimited length, such as tapped holes, polygonal holes, internal splines, internal toothings, oil grooves etc., in metal objects having smooth or toothed rotational outer surfaces.

b. Prior Art A known method of shaping metal objects is by means of radial pressure exerted on the object by at least two tools whose shaping surfaces roll in the circumferential direction on the surface of the object, said object being plastically shaped in successively repeated cycles in which in the first phase of each cycle the object rolls along an inner shaping surface of each tool, said surface constituting a segment of a smooth or toothed cylindrical surface which is tangential internally to the cylindrical surface of the object to be treated. In the second phase of each cycle there is effected axial displacement of the object over a feed distance at the instant when the object loses contact with the tools.

There also exists a known method of making internal shapes by means of forging on swaging machines, which method consists in deforming material in the form of a sleeve with a core therein by means of simultaneous pressure exerted on the lateral surface of the treated object by shaping-jaws undergoing small reciprocating motions in a radial direction.

This method has the disadvantage that it is not possible to maintain a constant rotational speed of the material during the foregoing process due to the radial reciprocating movements of the tool, and also it is not possible to simultaneously form relatively complicated shaped such as toothings, threads, splines etc., while simultaneously shaping an outer profile.

Furthermore, in the case of cold treating, the forging process is very noisy.

SUMMARY OF THE INVENTION An object of the invention is to provide a method of plastically forming internal shapes which eliminates the above-mentioned disadvantages of the process of forging on swaging machines and which extends the field of application of the known method of rolling outer profiles by means of jaws with an inner shaping surface.

This objective is achieved by the method according to the invention in which the inner shape in the metal object is made simultaneously with the shaping of the outer surfaces of the object in successively repeated cycles so that in the first phase of each cycle the object rolls along the inner shaping surface of each tool while simultaneously the material of the object is plastically deformed on a core which is placed in the bore of the object, whereas in the second phase of each cycle there is effected axial shift of the treated object together with the core over a feed distance just at the moment when the object loses contact with the tool.

The axial shift is effected by means of a feed device whose action is synchronized with the movements of the shaping tools.

In a particular embodiment, when in the first phase of one cycle the outer surface and the inner surface or only the outer surface of the object are simultaneously shaped, over its total length (not exceeding the effective width of the shaping jaws), or a specific portion of the length of said object, the axial shift is not employed.

In a modification of the method accordingto the invention in which inner threads are formed in a sleeve, the axial shift of the sleeve is effected by turning the sleeve on the threads of an unrevolving core. The rotation of the sleeve is obtained by the shaping tools, the unrevolving threaded core in this case being supported so as to perform limited axial motion.

The shape of the bore in the object corresponds to the shape of the core which is used. The removal of the core from the object after the shaping process is fin- 1 ished offers no difficulty due to the elastic deformation of the material. In the case of rolling inner threads in a sleeve the core is screwed out after the process is finished.

The basic advantage of a rolling process with the aid ofjaws having an inner shaping surface is that the area of plastic deformation extends much deeper into the material of the treated object than is the case in any other rolling process. Thereby it is possible to internally shape sleeves having a relatively thick wall and it becomes possible to make relatively complicated inner shapes, such as inner toothings, threads, holes with irregular outline and the like.

As essential advantage of the method according to the invention is the possibility of making inner profiles of theoretically unlimited length, which is unobtainable in the known methods of machine cutting. The result is that the treating method privides possibilities for shaping finished inner profiles having shapes which are not easy to make by machine cutting nor by any other method of plastic treatment.

The method according to the invention affords the possibility of making an outer profile while simultaneously shaping an inner profile on the core, such as a thread or splines. In the case of using multistage cores, it is possible to make holes of different shapes in each stage. A cold shaping process as well as a warm shaping process can be carried out smoothly without any objectionable noise.

In the particular embodiment of the process in which inner threads are formed on a sleeve on an unrevolving core, an essential advantage is the obtainment of the automatic feed of the sleeve resulting from the properties of the thread. Thereby, it is possible to eliminate expensive special devices for successively feeding the sleeve. This enables the construction of the machine tool to be considerably simplified. The length of the operating part of the core is independent of the length of the thread being shaped and it does not exceed the width of the shaping jaws. A machine tool operating according to this method can be easily automated. The objects to be shaped may be placed in a container from which they will be put on the core at one of its ends, and during the rolling process there will take place an automatic shift of the object with the rolled thread to the other end of the core where the finished object will fall into a receptacle. A particularly advantageous arrangement is a vertical disposition of the machine tool.

BRIEF DESCRIPTION OF THE DRAWING FIGS. la-lf diagrammatically illustrate in crosss'ection the individual stages of shaping the exterior and interior wall of a sleeve member;

FIGS. 2a-2f diagrammatically illustrate in longitudinal cross-section different arrangements in respect of the shape of the jaws, the manner of locating the core in the sleeve members and by the method of feeding the material into the working zone of the jaws;

FIG. 3 is a longitudinal sectional view of a modified arrangement for shaping the sleeve member in which the sleeve member can rotate with the core, the sleeve being axially advanceable on the core which is axially fixed; and

FIG. 4 is a longitudinal cross-section of an arrangement for shaping a threaded hole in a sleeve, the core being fixed against rotation.

DETAILED DESCRIPTION Referring to FIGS. la1f of the drawing therein is seen a sleeve 1 surrounded by two jaws 2 and 3. The sleeve receives a core 4 whose outer surface is formed with longitudinal ridges 5 for a purpose to be explained more fully hereafter. The sleeve 1 is to be plastically deformed by the jaws so as to assume a particular external shape and a particular configuration of the inner bore, i.e., splines, threads or the like.

Referring to FIG. la herein is seen the initial position of jaws 2 and 3 at a maximum spacing from the sleeve 1. Each jaw is coupled to a rotary drive means (not shown) of conventional construction so as to be driven in rotation about a center which is offset from the longitudinal axis of core 4. FIGS. la-lfshow in solid lines the circular path of the lower jaw 3 about center 0. The upper jaw 2 rotates about center 0'. The centers 0 and 0 are each offset by a distance e from the longitudinal axis of core 4, the distance between centers being 2e as shown. The jaws 2 and 3 undergo clockwise rotation as shown in FIG. and the jaws contact the outer periphery of the sleeve and apply deforming pressure on the sleeve as they roll thereon as shown in FIGS. lc1e In FIGS. 1a, lb and 1f the jaws are separated from the sleeve and during the time interval in which the jaws travel from the position shown in FIG. 1e to the position shown in la and are spaced from the sleeve, the sleeve can be longitudinally advanced by an axial feed distance up to a maximum approximately equal to the effective width of the jaws 2 and 3.

As a consequence of the direct action of the jaws on the sleeve, shaping of the outer surface of the sleeve is effected with simultaneous flow of the material within the bore of the sleeve to assume the shape of the outer surface of the core 4 which has been previously introduced therein.

The degree of plastic deformation of the sleeve is determined by the amount of interference between the path of travel of the jaws and the outer surface of the sleeve.

FIGS. 2a-2f show in axial section various arrangements for mounting the sleeve on the core to effect different modes of deforming of the sleeve. In FIGS. 2a2f similar reference characters will be used to designate elements corresponding to those in FIGS. la-lf.

Referring to FIG. 2a herein is shown an arrangement where core 4a extends in entirety through sleeve la. The core and sleeve are fed along successive axial steps to achieve shaping of the outer surface and of the inner bore of the entire sleeve. When the jaws begin to lose contact with the sleeve (as explained previously with reference to FIGS. lalf) the core 4a and sleeve la are axially fed through jaw 2a and 3a over a predetermined feed distance, after which the jaws close and shaping of the outer surface of the sleeve and simultaneous plastic flow of the material of the sleeve to fill the space between the ridges in the outer surface of the core 4a is effected so that the sleeve can be formed with an inner spline, threads or the like. The arrangement in FIG. 2a is such that the material of the sleeve can flow axially in two directions.

FIG. 2b differs from that in FIG. 2a in that the sleeve 1b is closed at its right-hand end whereby the material of the sleeve 1b can flow axially in only one direction.

FIG. 2c shows a core 40 with steps 9, l0 and 11 and step 9 has a shoulder abutting the right-hand end of sleeve 10 to prevent axial flow thereat of sleeve 10. Looking members 12c are secured on step 11 of core 4c and abut the left end of sleeve lc to prevent axial flow of the sleeve thereat. Hence, in the arrangement of FIG. 20 axial flow of the material of the sleeve is prevented in both directions.

In the arrangement in FIG. 2d, the jaws 2d and 3d are formed with opposed lips 20, 21 and 22, 23 for axially engaging the opposite ends of sleeve ld to prevent axial flow of the material of the sleeve in both directions. In the arrangement of FIG. 2d the width of the sleeve Id is less than the width of the jaws and a separate sleeve is shaped in each cycle of operation of the jaws. A plurality of sleeves 1d can be located in spaced relation along core 4d and the sleeves are inserted in succession between the jaws during the feed step.

FIG. 2e shows an arrangement similar to FIG. 2d but without any lips on the jaws whereby the material of sleeve 1e can flow axially in both directions during the period of deformation.

FIG. 2f shows an arrangment of a stepped core 4f which prevents axial flow of the material of the sleeve in opposite directions.

In the arrangement in FIG. 3 the core 4x turns together with the shaped material of the sleeve 1x, but it is axially fixed and does not undergo any axial displacement. In the successive cycles, when the jaws 2x, 3x lose contact with the sleeve 1x, the latter is axially shifted on core 4x over a feed distance. The length of the working part of the core 4): is less than the length of the hole being shaped.

FIG. 4 is directed to an arrangement where the sleeve ly is formed with inner screw threads, the sleeve being capable of being rotated while the core 4y is held fixed. As a consequence of the rolling of the material of the sleeve 1y along the inner surfacev of the jaws 2y and 3y, the outer diameter is reduced and simultaneously the material of the sleeve becomes tightly clamped against the unrevolving core 4y. Due to the rotation of the object 1y with the thus shaped inner thread in relation to the thread on the unrevolving core 4y, axial displacement of the core takes place, which is made possible by the presence of elastic element 15 between the core and its support 16. As soon as the jaws 2y and 3y lose contact with the material ly, the core is automatically displaced over a predetermined working stroke due to the release action of the elastic element 15. The process proceeds in successively repeated cycles as a result of the rotation caused by the movement of the jaws 2 y, 3y on the material of the sleeve ly in relation to the unrevolving threaded core 4y causing the working stroke to be obtained.

The shaping method is also suitable for the plastic treatment of non-metallic materials which are capable of plastic deformation.

What is claimed is:

1. A method of shaping a plastically deformable hollow sleeve comprising positioning a sleeve on a core within a space defined within a pair of opposed rotatable jaws, providing irregularities on the external surface of the core conforming to the desired internal deformed shape of the sleeve, rotating the jaws around the sleeve along an eccentric path to cause the jaws first to contact the sleeve and deform the sleeve to shape the external surface of the sleeve to the shape of the jaws while simultaneously deforming the inner surface of the sleeve so the material thereof plastically flows and conforms to the irregularities on the outer surface of the core, the jaws as they continue rotation along their eccentric path then losing contact with the thus shaped sleeve, and axially feeding the core over a feed stroke in the interval of time after the jaws have lost contact with the sleeve and before the jaws resume contact with the sleeve, said irregularities on the core being a screw thread, the axial feed of the core being effected automatically by elastically holding the core against axial displacement while rigidly preventing rotation of the core, the rotation of the jaws on the sleeve producing relative rotation of the sleeve on the core and axial displacement of the core against the elastic holding action, said core axially returning to its initial position by the elastic holding action when the jaws lose contact with the sleeve.

2. A method as claimed in claim 1 wherein said jaws are formed with inner surfaces which are segments of a cylinder.

3. A method as claimed in claim 2 wherein said sleeve is cylindrical and said jaws roll on the sleeve in tangential relation but with interference so as to produce the deformation and shaping of the sleeve.

4. A method as claimed in claim 1 wherein successive portions of the length of the sleeve are deformed by the jaws. 

1. A method of shaping a plastically deformable hollow sleeve comprising positioning a sleeve on a core within a space defined within a pair of opposed rotatable jaws, providing irregularities on the external surface of the core conforming to the desired internal deformed shape of the sleeve, rotating the jaws around the sleeve along an eccentric path to cause the jaws first to contact the sleeve and deform the sleeve to shape the external surface of the sleeve to the shape of the jaws while simultaneously deforming the inner surface of the sleeve so the material thereof plastically flows and conforms to the irregularities on the outer surface of the core, the jaws as they continue rotation along their eccentric path then losing contact with the thus shaped sleeve, and axially feeding the core over a feed stroke in the interval of time after the jaws have lost contact with the sleeve and before the jaws resume contact with the sleeve, said irregularities on the core being a screw thread, the axial feed of the core being effected automatically by elastically holding the core against axial displacement while rigidly preventing rotation of the core, the rotation of the jaws on the sleeve producing relative rotation of the sleeve on the core and axial displacement of the core against the elastic holding action, said core axially returning to its initial position by the elastic holding action when the jaws lose contact with the sleeve.
 2. A method as claimed in claim 1 wherein said jaws are formed with inner surfaces which are segments of a cylinder.
 3. A method as claimed in claim 2 wherein said sleeve is cylindrical and said jaws roll on the sleeve in tangential relation but with interference so as to produce the deformation and shaping of the sleeve.
 4. A method as claimed in claim 1 wherein successive portions of the length of the sleeve are deformed by the jaws. 